Ecological sanitation 3183830 221354105 2008-06-24T04:11:58Z Jaycorrales 358439 added Living machines to see also list '''Ecological sanitation''', also known as '''ecosan''', is a modern alternative to conventional [[sanitation]] techniques. The objectives are to offer economically and ecologically sustainable and culturally acceptable systems that aim to close the natural [[Biogeochemical cycle|nutrient and water cycle]]. Unlike most traditional sanitation methods, ecological sanitation processes [[human waste]] to recover [[nutrients]] that would otherwise be discarded. ==Introduction to ecological sanitation== Ecological sanitation (Ecosan) offers a new philosophy of dealing with what is presently regarded as [[waste]] and [[wastewater]]. Ecosan is based on the systematic implementation of reuse and [[recycling]] of nutrients and [[water]] as a hygienically safe, [[closed-loop]] and holistic alternative to conventional sanitation solutions. Ecosan systems enable the recovery of nutrients from human [[faeces]] and [[urine]] for the benefit of [[agriculture]], thus helping to preserve [[soil fertility]], assure [[food security]] for future generations, minimize [[water pollution]] and recover [[bioenergy]]. They ensure that water is used economically and is recycled in a safe way to the greatest possible extent for purposes such as [[irrigation]] or [[groundwater recharge]]. <ref>[Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) and International Water Association (IWA) (2003): “Greeting and opening session; Ecosan – a realistic tool to achieve the Millennium Development Goals”]</ref> According to the 10 Recommendations for Action, published at the 2<sup>nd</sup> international ecosan symposium 2003 in Lübeck, Germany, the main objectives of ecological sanitation are <ref>[Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) and International Water Association (IWA) (2003): “10 Recommendations for Action from the Luebeck Symposium on ecological sanitation”]</ref>: * To reduce the health risks related to sanitation, [[contaminated water]] and waste * To prevent the pollution of [[surface water|surface]] and [[ground water]] * To prevent the degradation of soil fertility * To optimise the management of nutrients and [[water resources]]. ==History of reuse-oriented sanitation approaches== In a very broad sense the recovery and use of urine and faeces has been practiced over millennia by almost all cultures. The uses were not limited to agricultural production (although for modern application this may be of most relevance), like the [[Ancient Rome|Romans]] who were well aware of the [[disinfecting]] attributes of urine and also used it for washing clothing. The most widely known example of the diligent collection and use of human [[excreta]] in agriculture is [[China]]. Reportedly, the Chinese were aware of the benefits of using excreta in [[crop]] production before 500 B.C., enabling them to sustain more people at a higher density than any other system of agriculture. The value of “[[night soil]]” as a [[fertiliser]] was clearly recognised with well developed systems in place to enable the collection of excreta from cities and its [[transportation]] to fields. Elaborate systems were developed in urban centres of [[Yemen]] enabling the separation of urine and excreta even in multi-storey buildings. Faeces were collected from [[toilet]]s via vertical drop shafts, while urine did not enter the shaft but passed instead along a channel leading through the wall to the outside where it evaporated. Here, faeces were not used in agriculture but were dried and burnt as [[fuel]]. In [[Mexico]] and [[Peru]], both the great [[Aztec]] and [[Inca]] cultures collected human excreta for agricultural use. In Peru, the Incas had a high regard for excreta as a fertiliser, which was stored, dried and pulverised to be utilized when planting [[maize]]. In the [[Middle Ages]], the use of excreta and [[greywater]] was the norm. European cities were rapidly urbanising and sanitation was becoming an increasingly serious problem, whilst at the same time the cities themselves were becoming an increasingly important source of agricultural nutrients. The practice of using the nutrients in excreta and wastewater for agriculture therefore continued in [[Europe]] into the middle of the 19th Century. [[Farmers]], recognising the value of excreta, were eager to get these fertilisers to increase production and urban sanitation benefited. <ref>[Bracken et al. (2006): “The Road Not Taken: How traditional excreta and greywater management may point the way to a sustainable future”]</ref> The increasing number of [[research]] and demonstration projects for excreta [[reuse]] carried out in [[Sweden]] from the 1980s to the early 21st century aimed at developing hygienically safe closed loop sanitation systems. Similar lines of research began elsewhere, for example in [[Zimbabwe]], in the [[Netherlands]], [[Norway]] and [[Germany]]. These closed-loop sanitation systems became popular under the name “ecosan”, “dewats”, “desar”, and other abbreviations. They placed their emphasis on the hygenisation of the contaminated flow streams, and shifted the concept from [[waste disposal]] to resource conservation and safe reuse. <ref>[UNESCO/IHP and Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH (2006): “Capacity building for ecological sanitation – Concepts for ecologically sustainable sanitation in formal and continuing education”]</ref> ==Concepts of ecological sanitation== Ecological sanitation (Ecosan) is a new holistic [[paradigm]] in sanitation, which is based on an overall view of material flows as part of an ecologically and economically sustainable wastewater management system tailored to the needs of the users and to the respective local conditions. It does not favour a specific sanitation technology, but is rather a new philosophy in handling substances that have so far been seen simply as wastewater and water-carried waste for disposal. <ref>[Werner, Christine (2006): “Closing the loop through ecological sanitation”]</ref> According to Esrey et al. (2003) <ref>[Esrey, Steven A., Andersson, Ingvar et al. (2003): ”Closing the Loop – Ecological sanitation for food security”]</ref> ecological sanitation can be defined as a system that: * Prevents [[disease]] and promotes [[health]] * Protects the environment and conserves water * Recovers and recycles nutrients and [[organic matter]] Ecosan offers a flexible framework, where centralised elements can be combined with decentralised ones, waterborne with dry sanitation, [[high-tech]] with [[low-tech]], etc. By considering a much larger range of options, optimal and economic solutions can be developed for each particular situation. <ref>[Jenssen, Petter D., Heeb, Johannes et al. (2004): “Ecological sanitation and reuse of wastewater. ecosan. A thinkpiece on ecological sanitation”]</ref> The figure below shows the potential positive impacts of an optimal ecosan approach: [[Image:gtz-advantages-of-ecosan.jpg]] Thus, the most important advantages of ecological sanitation systems are: * Improvement of health by minimising the introduction of [[pathogen|pathogens]] from human excreta into the water cycle * Promotion of safe, hygienic recovery and use of nutrients, organics, trace elements, water and [[energy]] * Preservation of soil fertility * Contribution to the conservation of resources through lower water consumption, substitution of mineral fertiliser and minimisation of water pollution * Improvement of agricultural productivity and food security * Preference for modular, decentralised partial-flow systems for more appropriate cost-efficient solutions adapted to the local situation * Promotion of a holistic, interdisciplinary approach * Material flow cycle instead of disposal of valuable resources ==Technologies of ecosan systems== Determining ecosan systems as ecological sanitation is not easy, for it is not just one specific technology, but a new approach based on an ecosystem-oriented view of material flows. The following diagram gives an overview of the different collection, treatment and reuse possibilities of the five flow streams considered in ecological sanitation systems: [[Image:gtz-technologies-for-ecosan.jpg]] Further information on ecosan technologies can be found in "Ecological Sanitation" by Winblad et al. <ref>[Winblad, Uno and Simpson-Hébert, Mayling. (2004). Ecological Sanitation - revised and enlarged edition]</ref>, in "Toilets that make compost" by Peter Morgan <ref>[Morgan, Peter. (2007). Toilets that make compost. Low-cost, sanitary toilets that produce valuable compost for crops in an African context]</ref> or in the gtz-ecosan technical data sheets <ref>[GTZ technical data sheets. http://www.gtz.de/en/themen/umwelt-infrastruktur/wasser/9397.htm]</ref>, among other relevant literature. ==Project examples== Examples for ecosan projects can be found among others in the collection of project data sheets of gtz ecosan <ref>[GTZ project data sheets. http://www.gtz.de/en/themen/umwelt-infrastruktur/wasser/9399.htm]</ref> or on the Enhanced Global Map of ecosan activities by EcoSanRes <ref>[EcoSanRes Global Map of ecosan activities. http://www.ecosanres.org/]</ref>. In the following some examples are given that underline the diversity of ecosan projects: '''Gunaxi province, China - large-scale project of urine diverting dehydration toilets''' The dissemination programme of ecological dry toilets for [[Hsinchu County|Guanxi]] province, one of the poorest provinces in China, started in 1997 with support of [[UNICEF]], SIDA and the [[Red Cross]] and has been expanded to 17 provinces until the year 2003. By this year, the scale of the project had increased to approximately 685,000 toilet units – today more than one million double vault urine diversion dehydration toilets (UDDTs) are installed in rural areas of China. In UDDTs, urine and faeces are collected separately: The urine is collected in the front and lead by a plastic pipe to a storage canister from where it can be used as a fertilizer in agriculture, the faeces fall at the back in one of two ventilated storage chambers and are covered with ash for better dehydration. After about one year of storage the dried material can be removed and used as a soil conditioner in agriculture. <ref>[GTZ. (2005). Urine diversion dry toilets dissemination programme Guanxi province, China. Ecosan project data sheet #005. Available at: http://www.gtz.de/en/themen/umwelt-infrastruktur/wasser/9399.htm]</ref> '''KfW, Frankfurt, Germany - vacuum toilets + greywater treatment''' The sanitation concept of the modern office building “Ostarkarde” of the [[KfW]] Bankengruppe in Frankfurt is based on a separate excreta and greywater collection. While urine and faeces are collected via vacuum toilets and a [[vacuum]] sewerage using much less water for flushing, the greywater from [[hand washing]] and kitchen is collected and treated separately in a compact [[activated sludge]] reactor combined with [[membrane]] [[filtration]]. The treated greywater is then reused for toilet flushing and cleaning water. The amount of greywater can be reduced by 76% by this cost-efficient system which could be one of the prior choices for sanitation systems of newly constructed office buildings. <ref>[GTZ. (2005). Vacuum sewerage and greywater recycling, office building "Ostarkade" of the KfW Bankengruppe Frankfurt am Main, Germany. Ecosan project data sheet #001. Available at: http://www.gtz.de/en/themen/umwelt-infrastruktur/wasser/9399.htm]</ref> ==References== {{reflist}} ==See also== * [[Allotment gardens]] * [[Biofilter]] * [[Biogas]] * [[Community-led total sanitation]] * [[Composting toilets]] * [[Constructed wetlands]] * [[Folkewall]] * [[Greywater]] * [[Human feces]] * [[Human urine]] * [[Humanure]] * [[Living machines]] * [[Outhouse]] * [[Sanitation]] * [[Sewage treatment]] * [[Sustainable sanitation]] * [[Urban agriculture]] * [[Urban horticulture]] ==External links== * [http://www.borda-net.org Bremen Overseas Research and Development Agency (BORDA) (Germany)] * [http://www.ecosanres.org/ EcoSanRes (Sweden and International)] * [http://www.ecosan.at/ EcoSan Club (Austria)] * [http://www.ecosan.no/ Ecosan Norway - Norwegian University for Life Science UMB] * [http://www.ecosan.ph/ Ecosan (Philippines)] * [http://www.drytoilet.org/ Global dry toilet organization (Finland)] * [http://www.gtz.de/ecosan/ gtz - ecosan programme (Germany)] * [http://www.ecosan.org/ IWA (International Water Association) Ecosan Group] * [http://aquamor.tripod.com/page2.html/ Morgan, Peter, Aquamor (Zimbabwe)] * [http://www.nlh.no/research/ecosan/ NLH (Norway)] * [http://www.sandec.ch SANDEC (Switzerland)] * [http://www.sarar-t.org/index.php/ SARAR Transformación (Mexico)] * [http://www.undp.org/water/initiatives/ecol.html UNDP Ecosan Website] * [http://www.uni-hohenheim.de/respta/ University Hohenheim - RESPTA (Germany)] * [http://www.ecosan.nl/ WASTE (Netherlands)] [[Category:Sewerage]] [[Category:Environmental engineering]] [[Category:Urban agriculture]] [[Category:Sustainability]] [[de:Ecosan]]